Provided are an optical disc discrimination method, an optical disc device and an integrated circuit that enable to accurately discriminate the type of an optical disc. The optical disc discrimination method comprises a first seeking step (S3) of performing a seek operation to a predetermined reference address in a user data area; a second seeking step (S5) of performing a seek operation from the reference address sought in the first seeking step (S3) to a predetermined target address in a physical information area, an address reading step (S7) of reading a current address at a position sought in the second seeking step (S5), and an optical disc type determination step (S8 through S10) of determining the type of the optical disc loaded in the optical disc device, based on the current address read in the address reading step (S7).
Legal claims defining the scope of protection, as filed with the USPTO.
1. An optical disc discrimination method for discriminating, from a plurality of types of optical discs having recording densities different from each other, the type of an optical disc loaded in an optical disc device for reading information recorded on the optical disc or for recording information on the optical disc by irradiating a light beam onto the optical disc, the optical disc having a user data area and a physical information area having formats different from each other, the optical disc discrimination method comprising: a first seeking step of performing a seek operation to a predetermined reference address in the user data area; a second seeking step of performing a seek operation from the reference address sought in the first seeking step to a predetermined target address in the physical information area; an address reading step of reading a current address at a position sought in the second seeking step; and an optical disc type determination step of determining the type of the optical disc loaded in the optical disc device, based on the current address read in the address reading step.
2. The optical disc discrimination method according to claim 1 , further comprising: a third seeking step of performing a seek operation to the target address in the physical information area in accordance with the type of the optical disc determined in the optical disc type determination step.
3. The optical disc discrimination method according to claim 2 , wherein the plurality of types of optical discs include a first optical disc and a second optical disc having recording densities different from each other, in the second seeking step, the seek operation from the reference address sought in the first seeking step is performed to the predetermined target address in the physical information area is performed, using a conversion coefficient corresponding to the first optical disc between an address and a radial position of the optical disc, in the optical disc type determination step, judgment is made as to whether the current address read in the address reading step is equal to or larger than a predetermined threshold value, the loaded optical disc is determined to be the first optical disc in the case where the current address is judged to be smaller than the predetermined threshold value, and the loaded optical disc is determined to be the second optical disc in the case where the current address is judged to be equal to or larger than the predetermined threshold value, and in the third seeking step, the seek operation is performed from the current address read in the address reading step to the predetermined target address in the physical information area, using a conversion coefficient corresponding to the second optical disc between an address and a radial position of the optical disc, in the case where the loaded optical disc is determined to be the second optical disc in the optical disc type determination step.
4. The optical disc discrimination method according to claim 1 , further comprising: a provisional discrimination step of provisionally discriminating the type of the optical disc before the seek operation to the reference address is performed in the first seeking step, wherein in the second seeking step, a value of the target address is switched, based on a provisional discrimination result on the type of the optical disc in the provisional discrimination step.
5. The optical disc discrimination method according to claim 4 , wherein in the provisional discrimination step, the type of the optical disc is provisionally discriminated, based on at least one of the recording layer number derived from the number of focus error signals, the amplitude of a tracking error signal and the frequency of a wobbling groove.
6. The optical disc discrimination method according to claim 1 , wherein the plurality of types of optical discs are reproduced using a light source configured such that a predetermined reproduction power is set for the each respective type of optical disc, and the optical disc discrimination method further comprises a reproduction power switching step of switching the reproduction power to a lowest reproduction power of the reproduction powers for the plurality of types of optical discs, before the seek operation to the target address is performed in the second seeking step.
7. The optical disc discrimination method according to claim 1 , wherein the plurality of types of optical discs are reproduced using a light source configured such that a predetermined high-frequency component for the each respective type of optical disc is superimposed on a drive current, and the optical disc discrimination method further comprises a direct-current driving step of stopping superimposition of a high-frequency component and of driving the light source by a direct current, before the seek operation to the target address is performed in the second seeking step.
8. The optical disc discrimination method according to claim 1 , wherein the optical disc of each respective type is driven and rotated at a predetermined linear velocity, and the optical disc discrimination method further comprises a rotation driving step of driving and rotating the optical disc at a highest linear velocity of the linear velocities for the plurality of types of optical discs, before the seek operation to the target address is performed in the second seeking step.
9. An optical disc device for reading information recorded on one of a plurality of types of optical discs having recording densities different from each other, or for recording information on the optical disc by irradiating a light beam onto the optical disc, the optical disc having a user data area and a physical information area having formats different from each other, the optical disc device comprising: a first seeking section which performs a seek operation to a predetermined reference address in the user data area; a second seeking section which performs a seek operation from the reference address sought by the first seeking section to a predetermined target address in the physical information area; an address reading section which reads a current address at a position sought by the second seeking section; and an optical disc type determination section which determines the type of the optical disc loaded in the optical disc device, based on the current address read by the address reading section.
10. An integrated circuit for discriminating, from a plurality of types of optical discs having recording densities different from each other, the type of an optical disc loaded in an optical disc device for reading information from the optical disc or for recording information on the optical disc by irradiating a light beam onto the optical disc, the optical disc having a user data area and a physical information area having formats different from each other, the integrated circuit comprising: a first seeking circuit which performs a seek operation to a predetermined reference address in the user data area; a second seeking circuit which performs a seek operation from the reference address sought by the first seeking circuit to a predetermined target address in the physical information area; an address reading circuit which reads a current address at a position sought by the second seeking circuit; and an optical disc type determination circuit which determines the type of the optical disc loaded in the optical disc device, based on the current address read by the address reading circuit.
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March 3, 2011
December 18, 2012
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